Apparatus for hydrocarbon oil conversion



March 22, 1932. J. B. HEID APPARATUS FOR HYDROCARBON OIL CONVERSION Filed Sept. l0. 1926 faQ/,v

Fatented Mar. 22, 1932 UNITED STATES PATENT 'oFElcE v JACOB BENJAMIN REID, OF CHICAGO, ILLINOIS, ASSIGINOIR TO UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA APPARATUS FOR H YDBOCARBON OIL CONVERSION I y Application led September 10,1926. Serial No. 134,602.

The resent improvements relate more particular y to the conversion of hydrocar ons of high boiling point range intohydrocarbons of low boiling point range having gasoline-like characteristics.

More specifically, the present improvements have to doiw'ith those processes in which a dephlegrriator or refiux condenser is utilized andl the particular improvements comprise more eiicient dephlegmation and fractiorfvtion of the vapors and the stripping from the reflux condensate of refractory frac-l tions having an intermediate boiling point range. y y

The eiiiciency of standard types of dephlegmators used incracking processes is only' such that a large amount of products taken oit as final products from the top of the-dephlegmator is condensed and with/drawn from the bottom thereof with theeflux condensate.

In processes wherein the reflux condensate is returned to the heating, crackingand reacting zone for retreatment, the presence 'of light gravity fractions in the condensate impairs the efficient operation ofthe process,

inasmuch as it reduces the capacity of the plant and the production of the lightgravity overhead distillates having gasoline-like characteristics.

The present invention proposes to submit the reflux condensate before it leaves the fractionating or dephlegmating tower' to a reboiling action. for which heat will be fur.- nished by the. incoming vapors.

Many advantages and obiects will be hereinafter more particularly described.

In the drawings, A

Fig. 1 is an enlarged vertical sectional view, partly broken away, of thedephlegmator.

Fig. 2 is a cross sectional view taken on line 3 3 of Fig. 1. l

Fig. 3 is a fragmentary vertical cross sectional view illustrating a reboiler tray with liouid overfiow. y

Referring more particularly to the drawings` the vapors from the cracking' process are introduced to dephlegmator 8 through inlet 15.

During the upward passage of the vapors Referring lnow more particularly to the through the dephlegmator 8, the vapors will be subjected to a retarding and baffling action so that they will have a back and forth travel while simultaneously being subjected to they action of the cooling medium, such, for instance, as the charging stock introduced through line 6, or any othercooling medium, which may be introduced through line 18, controlled by valve 19, as will be obvious to those lskilled in the art. v The vapors remaining uncondensed after passage upwardly through the dephlegmator 8 may be withdrawn through the vapor outlet pipe 20, and

directed to condensing coil (not shown),

where they are condensed.

During the upward passage of the vapors /though the dephlegmator 8, the heavy ends will be condensed and will collect in the lower portion of the dephlegmator as reflux condensate: .This refiux condensate, mixed with the unvaporized portion of the charging stock when the latter is introduced into the dephlegmator'through pipe 6),- may be withdrawn through the reflux leg 32.

novel features of the present invention, in operatingthe process it is desirable to so regulate the temperature of the vapors leaving the top of the dephlegmator as to produce a prod. uct having a boiling point range conforming to the specifications for commercial gasoline. The advantages of this, of course, are the elimination of further redistillations and fractionations of the pressure distillate. with its attendant increased costs and treating losses. Howevenin so controlling the temperature as to produce such a product, those fractions of an intermediate boiling point range between the gasoline-like fractions and thereflux condensate fractions will be condensed and form part of the refiux condensate. More specifically, these fractions' of in'- term'ediate boiling point range comprise a kerosene-like fraction, which has been found to be very refractory and difticult'to recrack. It is desirable. therefore. in processes making a gasoline like product directly from the top of the dephlegmator to provide for the effective treatment of the redux condensate, in- ,100

cluding these kerosene-like fractions, in order to have an efficiently operating process.

The present invention proposes to collect pools of reflux condensate on supeiposed pans or trays. The vapors entering the dephlegmator will be forced to pass around these trays, coming iii Contact with the liquid there, thus producing a reboiling. The light gravity fractions will be vaporized and will as, cend upwardly with the vapors remaining uncondensed.

In the dephlegmator 8, there are provided spaced superposed pans 38 and 39. Preferably, two pans, 38 and 39, comprise a set, being respectively of such dimensions that the pans leave alternately a space at the center of the dephlegmator and a space at the edge of the pan and the shell of the dephlegmator. This arrangement is to provide for a circuitous path of the vapors ascending in the dephlegmator, first between the edge of a pan and the dephlegmator shell, then through the center opening of the pan immediately above, and continuing this back and forth throughout the height of the dephlegmator.

As a feature of the invention, each pan 38 is imperforate and is provided with an annular flange of substantial height to permit the condensate to accumulate thereon in a substantial pool. The central opening 40 is also provided with a flange above and below the horizontal plane of the pan 38, as shown. Each pan 39 is provided with an annular flange 41 extending above and below the horizontal plane of the pan.

Condensate collecting on pan 38 will overflow through overflow pipes 42 (the height of which, above the horizontal plane of pan 38, determines the liquid level) discharging said overflowing liquid onto the pan 39 therebelow. Each pan 39 is also provided with a central flange 43, open at its top and closed at its bottom, and extending above and below the horizontal plane of the pan. The height of the flange above the horizontal plane of the pan 39 determines the height ofthe liquid pool on the tray. Condensate overflows from pan 39 through the overflow 43 and into the pipes 44. These pipes 44 are in the shape of radial arms which direct the condensate to various points on the pan 38 therebelow.

The operation of the dephlegmator and the reboiling feature will be apparent to those skilled in the art. T he vapors will have imparted thereto a back and forth circuitous travel, as illustrated by the arrows in Fig. 1. As the vapors come in contact with the surface of the pools of liquid condensate in each pan, a reboiling of this liquid condensate is effected, and through heat exchange a vaporization of the light gravity fractions contained therein. This in effect creates a small still oii each fray and results in a gradual decrease of the temperature of the vapors as they ascend through the tower and a gradual travel v increase in the reflux condensate as it flows downwardly from tray to tray. Due to the mean temperature between the vapors and the condensate in each tray, a redistillation effect is secured, and in this manner it is possible to obtain a reflux at the bottom of the tower, having an initial boiling point range equal to or higher than the end boiling point of the distillate produced at the top of the tower.

As the vapors sweep over the pool of condeiisate on each tray at a comparatively high velocity and in a continually whirling course, the heavy particles are forced to the outer path and against the surface of the condensate on each tray. This whirling or centrifugal actionof the `vapors forces the heavy particles in the vapors to the outer path and against the surface of the condensate on each tray, which immediately converts them into a liquid giving up the heat of vaporization to the condensate and reboiling the lighter hydrocarbons which remain on each tray.

I claim as my invention:

1. As an article of manufacture, a unit for insertion in a dephlegmating column of an oil cracking apparatus, said unit comprising interconnected. spaced apart, upper and lower pan sections, the lower pan section being of greater diameter than the upper pan section, the outer wall of the lower pan section being constructed to snugly fit the interior wall of the dephlegmating column, a vapor opening through said lower pan section, liquid overflow pipes carried by said lower pan section, an overflow well carried by and centrally disposed with respect to said upper pan section, radially extending conduits connected with said overflow well for delivering overflow liquid from said upper pan section to spaced points in said lower pan section.

2. In a dephlegmator having a shell, a transverse partition having an upwardly extending flange surrounding an aperture therein, means for connecting the periphery of said partition to said shell, whereby a pool of liquid may be supported by said partition between said shell and said flange, a tray supported below said aperture having a rim adapted to contain another pool of liquid, and means extending below said partition, surrounding said aperture and terminating substantially in the plane of the upper edge of said rim adapted to cause the ascending vapors prior to passing through said aperture to sweep over the surface of the pool of liquid in the tray therebelow and to be deflected downwardly thereagainst.

3. In a dephlegmator having a shell, a pair of spaced transverse partitions having aligned central apertures through which ascending vapors pass, a tray interposed between said partitions for preventing direct passage of vapors from the aperture therebelow to the aperture thereabove, said tray extending toward the shell but terminating short thereof leaving an annular space for passage of vapors, said tray havin an annular rim extending both upwarv ly and downwardly therefrom, said rim extendin the greater part of the vdistance between sai partitions. v

4. A dephlegmating apparatus comprising a vertical shell, a tray within the shell having a rim adapted to retain a pool of liquid, said rim being spaced from the walls of the shell to provide a vapor passage adj acent the shell walls, an overflow well within said rim and extending below the bottom of the tray, means for introducing liquid to said pool at a point remote from said well, a second tray below the first-mentioned tray and extending to the walls of the shell, a second vapor passage through said second tray and positioned beneath said well, means for retaining liquid on said second tray, and means for discharging liquid from said well onto said second tray.

JACOB BENJAMIN HEID. 

